@Ch40zzC0d3r and @Firoball The advice about multiplayer was for me personally and after talks about my actual skill levels.

@All everything after the dash "-" is my elaboration on the Bullet-point of Superku's advice and should not be taken as a direct quote, more a mixture of the advice and my conclusions.

@Superku, yes I only meant to attribute the bullet points to you.
We do still disagree and design doc's and laying out full details. I would assume this is because you haven't worked as the unpaid-programmer at the whim of a designer or worked with a designer that is a 100% art person with little to no coding. the stories I could tell you about how if the designer would just fully express what he wanted in a doc, and how it would have saved me 20+ rewrites of every action, function or part of a function.... IT's maddening. The artist had me rewriting for days to make a bullet casing fall out of the gun in the proper way. Starting with no physics and ending in physics looking to non-cinematic. Designers that wish a player to act as if in a movie but write 3 lines of a doc... Maddening!
I understand your views from a solo developer, I hope you can see mine as a long time hired-gun(not implying pay lol).

Your Great Bro,
I might talk mostly on a path for newbies to learn, but once they do this is the advice they should focus on for a first game.